Park ranger inspects a boat for aquatic invasive species (Glacier National Park photo)

HELENA -

Glacier National Park announced in a press release on Thursday that in response to the recent detection of invasive mussel populations in central Montana, the park has issued an interim boating closure within all park waters.

The measure is being implemented in accordance with the park’s Aquatic Invasive Species (AIS) Action Plan, and the closure includes both motorized and hand-propelled watercraft.

The 2014 plan calls for the immediate closure when invasive mussels are detected within a waterway in the State of Montana, as was announced on November 9 by Montana Fish Wildlife, and Parks.

The park will begin an assessment period to conduct testing, inspect park boats, and evaluate the risk boats pose to park waters and waters downstream from the unintended introduction of invasive mussels.

The assessment will likely include the evaluation of further tests of waters across the State of Montana during the summer of 2017. The closure will remain in place during the assessment period, which will extend until the nature of the threat is better understood.

“Park scientists will work diligently with the State of Montana and other water quality experts to understand the scope of this threat, and identify steps the park will take to further protect our waters in the Crown of the Continent,” said park superintendent Jeff Mow.

Glacier National Park sits at the top of three continental scale watersheds. Water from the park drains into the Columbia, Missouri, and South Saskatchewan Basins. Protecting park waters from an infestation is important not only for the park’s ecosystem, but also to economic and ecological interests downstream, according to Park officials.

Beginning in 2011, the park initiated a mandatory boat inspection and launch permit program to reduce the risk of infestation of park waters by invasive mussels. Since that time, approximately 1,000 motorized boat permits were issued annually. The park also required self-inspection and AIS-free certification of non-motorized watercraft. These boats come from many states across the country, including those with established populations of invasive mussels.

In 2016, launch permits were issued to boats registered in 13 mussel positive states following inspection.

Water samples from Tiber Reservoir east of Shelby have tested positive for the larvae of aquatic invasive mussels, with similar tests from Canyon Ferry Reservoir near Helena showing “suspect” or inconclusive results, according to officials at Montana Fish, Wildlife and Parks.

“This is the first positive test in Montana for the larvae of quagga or zebra mussels,” said Eileen Ryce, FWP fisheries division administrator. “Although we hoped we would never see these invasive species in Montana waters, we’ve been preparing for this possibility for some time, and we’re going to work together to address this threat.”

Recent site inspections at Tiber and Canyon Ferry did not turn up any established populations of adult mussels, but officials will be conducting more extensive inspections with the assistance of stakeholders such as dam operators, marina concessionaires and other groups.

FWP for many years has conducted regular testing of the state’s rivers, lakes and reservoirs for aquatic invasive mussels.

Water samples from Fresno, Holter, and Hauser reservoirs have come back negative, as did samples from Lake Frances, the Marias River, and the Milk River. Testing at Fort Peck Reservoir and the entire Missouri River system is underway.

“The recent test results are definitely bad news, but they do indicate our detection system is working,” said Ryce. “The results from Tiber Reservoir show the larvae exist at very low densities, which improves our chances for containment.”